Stabilizer pad



Jan. 2, 1962 J, ALDRED, JR. 3,015,497

STABILIZER PAD Filed Feb. 18, 1959 INVENTOR. J a%/? l. flZJ/ad J United States Patent Ofice 3,015,497 Patented Jan. 2, 1962 3,015,497 STABILIZER PAD John L. Aldred, Jr., Bloomfield Hills, Mich, assignor, by

mesne assignments, to Ford Motor Company, a corporation of Delaware Filed Feb. 18, 1959, Ser. No. 794,057 2 Claims. (Cl. 280-150) This invention relates to stabilizers for vehicles, particularly for tractors, trucks and like vehicles which carry equipment such as diggers, cranes, hoist apparatus, etc. The invention is especially concerned with an improved stabilizer pad, that is, the part that engages the ground when the stabilizer is lowered to stabilize the vehicle against tipping due to ofl-center loads imposed on it by operation of the mounted implement.

In the use of such implements on mobile equipment, such as for example, tractor mounted back-hoes, a rigid pad carried by a stabilizer arm is moved from a folded position to an operative position when the back-hoe is made ready for digging. In the operative position, the pad is forced into contact with the ground, the condition of which varies greatly in that it may be smooth, uneven, hard, soft, wet or dry. The stabilizer arms are usually of variable length to compensate for uneven terrain generally, but local roughness or unevenness is not compensated for.

Attempts to improve stabilizers by hinging the pad above their centers of effort to compensate for uneven local terrain have been unsuccessful because the pads rock and are unstable. A possible exception is when a hinged pad is used on a very hard surface such as concrete, macadam or an auxilairy platform of large area.

In the normal use of a tractor mounted back-hoe or similar implement, all kinds of different supporting surfaces are encountered and my improved stabilizer will operate on any surface capable of supporting the load imposed without difficulty and with excellent stability.

Accordingly, it is the object of my invention to provide an improved stabilizer and stabilizer pad for mobile equipment which will overcome the aforesaid difiiculties.

Reference is made to the accompanying drawing for a specfiic example of my improved device. In the drawmg:

FIG. 1 is a perspective veiw of a tractor-mounted backhoe with stabilizers embodying my invention mounted on the back-hoe frame;

FIG. 2 is an enlarged sectional view of the stabilizer arm and pad mounting; and

FIG. 3 is a view like FIG. 2, but showing the parts in different relative positions.

Referring to FIG. 1, it will be seen that a back-hoe having a swing frame 12 is mounted in a tractor 14 of the so called industrial type. The back-hoe frame 16 carries oppositely disposed stabilizers having arms 18 and pads 20. The arms 18 are preferably of box-section and are pivotally mounted at 22 to the main frame 16 of the back-hoe. A control arm 24 is pivotally connected to arm 18 at 26, and at its other end to a cylinder 30 at 28. The cylinder 30 is movable vertically on a piston rod 32 under the influence of hydraulic pressure from the fluid pressure supply of the implement (not shown). This structure is duplicated on the other side of the vehicle.

The back-hoe 10 has the usual dipper, boom, actuating cylinders, etc., which have nothing to do with the present invention so will not be described. While a backhoe has been shown by way of example, the advantages of my invention are equally applicable to other tractor (or truck) mounted implements.

During travel of the tractor 14, the stabilizers are normally folded with the pads 20 out of ground contact. This is accomplished by admitting pressure fluid to the bottom of cylinders 30 which causes upward movement of said cylinders on the rods 32 which, in turn, causes the arms 18 to be swung upwardly about the pivots 22.

When the tractor arrives at a work site, the stabilizers are swung into ground engaging position preparatory to digging. This is accomplished by admitting pressure fluid into the upper ends of cylinder 30 which moves the inner ends of arms 24 downwardly and sets the pads 20 firmly on and into the ground.

As will be seen from FIGS. 2 and 3, the pad 20 is conical in shape and is preferably formed of steel. The arm 18 has a boss 34 welded on its outer end. A stud 36 formed with a shoulder 38 is fixed in the boss by means of a nut 40 which threadedly engages the upper end portion thereof. The lower end of the stud is formed with a ball 42 which is retained in nested engagement with the pad 20 at the apex thereof by a cap 44. The latter is formed in the shape of a truncated cone and is welded to the pad around the base thereof.

It will be understood from the figures that the pad 20 may rotate around the ball 42 and is permitted limited angular movement relative to the axis of the stud 36. In fact, the pad 20 has limited universal movement about the ball 42.

This universal movement permits self adjustment of the pad as it is moved into ground engagement such that the maximum area of the pad is engaged with the terrain on which it rests. In soft ground the pad will embed itself in the position shown in FIGS. 1 and 3 and present a substantial area of the conic surface to the ground. In relatively hard or rocky terrain, as the pad is being set, any local hard spot, rock or obstruction will cause the pad to rotate or rock away from this local resistance and thus present an enlarged area to the adjacent softer terrain. This action will be stable provided there is suflicient bearing resistance within the limits encompassed by the pad area in contact, and provided that the hinge point is below the center of effort or the metacentric center of the conic column. Such placing of the pad will produce some stabilizing motion which will compensate for load variation during operation of the digger or other element.

Iclaim:

1. A stabilizer for mobile equipment, comprising, in combination: a stabilizer arm, a dished ground engaging pad formed of a surface of revolution having the general form of a flat, inverted cone, and means, including a pivot located centrally of the pad and immediately above the bottom of the inverted cone, mounting the pad for pivotal movement on the end of the stabilizer.

2. A stabilizer for mobile equipment, comprising, in combination: a,stabilizer arm, a dished ground engaging pad formed of a surface of revolution having the general form of a flat, inverted cone, and means, including a pivot located centrally of the pad and immediately above the bottom of the inverted cone, mounting the pad for limited universal movement on the end of the stabilizer.

References Cited in the file of this patent UNITED STATES PATENTS 1,093,750 Welby Apr. 21, 1914 1,494,161 Fairbanks May 13, 1924 1,574,679 Nilsson Feb. 23, 1926 1,958,114- Robinson May 8, 1934 2,375,264 Wagner et al. May 8, 1945 2,870,924 Wills Jan. 27, 1959 

